Rance,
This answer is probably too easy and obvious but...
Are the hold downs on the distributor cap like the GM HEI units? I'm not exactly sure what you're describing, but it sounds similiar.
If they are, they're spring loaded... Push down with a screwdriver, and turn about 180 degrees. There's a little finger that grips the bottom of the distributor. They (2) turn out of the way, and free up the cap.
